1. Field of the Invention
This invention relates generally to Engine Intake Accessories and, more specifically, to a Vacuum Relief Assembly for I.C. Engine Intakes.
2. Description of Related Art
After-market accessories for improving the performance of stock internal combustion engines has become a enormous industry. One particular focus of the performance accessory industry is that of intake systems. A performance-enhancing modification is to relocate the stock air intake duct from its normal location deep within the engine compartment. It has been determined that when the vehicle is operated in warm climates, the air within the engine compartment becomes very hot; this means that the stock engine is taking hot air into its intake system. As the intake air becomes hotter, the engine performance declines. One solution to this is to add a “cold air intake” assembly to the engine assembly. The cold air intake essentially relocates the intake inlet to a position low-down in the engine compartment, typically behind the front bumper—putting the air intake down and forward of its stock location provides the engine with cooler intake air (at least cooler than that available in the engine compartment).
One problem with relocating the air intake so low is that it can become clogged by water or debris thrown up from the road surface. As the intake inlet becomes clogged, the engine is starved for air, and begins to lose power and efficiency. FIG. 1 is an introduction to the conventional I.C. intake system.
FIG. 1 is a schematic diagram of pertinent portions of a conventional internal combustion engine assembly 30. The typical internal combustion engine 32 has an intake plenum 34 associated with it for delivering intake air to the engine 32. The plenum 34 has a throttle body 38 that adjusts the intake airflow into the plenum 34. Air is supplied to the throttle body 38 via the intake tube 40, which obtains air from the environment through an intake air filter 42. The filter 42 shown here is intended to simulate a cold-air intake previously discussed. Combustion gases exit the engine 32 via an exhaust manifold 36.
As discussed above, if the intake air filter 38 is clogged (such as by dowsing or submerging in water), insufficient air will be provided through the intake tube 40, throttle body 38 and plenum 34 for supporting combustion in the engine 32; poor engine performance will be the result. FIG. 2 depicts a prior art attempt at solving this problem.
FIG. 2 is an exploded perspective view of a prior art pressure relief valve for internal combustion engines 10. Specifically, the device is the “Intake Tract Negative Pressure Relief Valve for I.C. Engine” of Concialdi, U.S. Pat. No. 6,394,128. The Concialdi valve 10 consists of a pair of ring-shaped tubular elements 11, which are bonded to one another when the device 10 is assembled. Within the chamber created by the bonded tubular elements 11 is a foam spring element 18, having a resilient member 17 stretched over it. The resilient member 17 has several diaphragms 19 formed in it that are cooperatively designed to each cover an aperture 14 formed in the tubular elements 11. There is further a filter element 20 placed over the outer surface of the assembled tubular elements 11.
The Concialdi device is designed to be installed along the air intake tube (see FIG. 1) to relieve excess vacuum conditions within the air intake tube. In normal flow and pressure conditions, the diaphragms 19 seal the apertures 14, thereby allowing air to enter the system via the intake air filter (see FIG. 1). When the internal pressure within the intake tube drops too low, the diaphragms 19 will be pushed inwardly away from the apertures 14; this will permit air to flow in through the filter element 20 and the apertures 14, thereby providing additional combustion air to the I.C. engine. One problem with the Concialdi device is related to its installation; FIGS. 3A and 3B discuss this issue.
FIGS. 3A and 3B are schematic diagrams of the device 10 of FIG. 2 being installed in the assembly 30 of FIG. 1. In order to install the Concialdi device in an existing I.C. intake system (as is always the case), the intake tube 40 either must be replaced or modified by cutting to create a gap 41 in the tube 40 that is adequately sized to fit the valve 10 into it. Cutting this gap 41 into the tube 40 can be very challenging, and most times will require that the entire intake tube 40 be removed from the engine compartment.
A further defect in the Concialdi device is related to its long-term durability and reliability. Because the spring element 18 is made from foam material (“ foam rubber”), it is expected to decay and deteriorate over time, due to the constant flow of air past it. As the spring element 18 deteriorates, it will provide less and less biasing force against the diaphragms 19, which ultimately results in the seals between the diaphragms and the apertures 14 to fail (allowing air to bypass the normal intake air filter).
What is needed, then, is a device that prevents an under-pressure condition in the intake tube of an internal combustion engine. Furthermore, this device must be easily installed in existing intake air tracts and must demonstrate superior durability and reliability.